Is "N/A" the right thing to report? Would something like "Unknown" or
"Unreported" be better?

+ 3 * sizeof(char));
+ if (!ptr)
+ dev_err(dev, "Failed to inform that firmware version is
unavailable to the adapter\n");

The sentence structure here seems awkward. I would probably just get rid of
this error and this one later in the function.
dev_err(dev, "Failed to isolate FW level string\n");
Instead just check and report if adapter->fw_version == NULL in the complete:
label section.
-Tyrel